The wind is always blowing somewhere, but deciding where to locate a wind farm is not always easy. Now a team of researchers at Penn State University has designed a model that can identify the best place to build a wind farm.
“Normally, people planning to build a wind farm will look for good terrain and an average wind speed that is not too strong and not too weak, but consistent,” said Guido Cervone, professor of geography, and meteorology and atmospheric science. “We found a more accurate and efficient way to look at wind predictability at specific locations, a key factor when considering building a new wind farm. With fossil fuels and nuclear energy you know exactly how much energy you will have. But wind is not like that.”
Location, for general electrical output, is important, but being able to predict how much wind energy the farm will be able to produce 24 hours in the future is also important. Electricity suppliers purchase the energy produced by wind farms and want reliability. Wind farms routinely sell their electrical output to the suppliers, but they would also like to be able to schedule, 24 hours in advance, how much power they will produce.
Cervone and Mehdi Shahriar, recent Penn State doctoral recipient in energy and mineral engineering, used the Analog Ensemble, developed by the National Center for Atmospheric Research, to analyze the errors in wind-farm electrical-production predictions across the country.
AnEn uses a historical set of past observations and predictions spanning at least several months, but preferably two years. It provides a probability model of the forecast, in this case the available wind for power production.
Researchers observed that locations with higher average wind speed are associated with larger degrees of forecast uncertainty which increases the difficulty to predict wind speed at these locations. Therefore, wind farm builders could choose locations with perhaps lower average wind speeds, but more consistent and predictable winds.
The model produces a probability curve for wind production from which companies can make decisions while understanding the risks. If the model says the probability of sufficient wind for electrical production is about 80%, both the wind farm owners and electricity buyers know the risk of winds being insufficient. If the probability is 20%, undoubtedly both would decide that the risk would be too great to rely on the wind farm for electricity.
(Source: Penn State)